Field of the Invention
The present invention relates to a developer container, a developing device, a process cartridge, and an image forming apparatus.
There is an image forming apparatus that forms an image on a recording material using an electrophotographic method. The image forming apparatus includes an electrophotographic copying machine. Alternatively, the image forming apparatus includes an electrophotographic printer such as a laser beam printer or a light emitting diode (LED) printer, a facsimile apparatus, and a word processor.
The process cartridge is a cartridge obtained by integrating a charging unit, a developing unit, or a cleaning unit and a photosensitive drum, and made removably mountable on a main body of an image forming apparatus.
Also, the process cartridge is a cartridge obtained by integrating at least one of a charging unit, a developing unit, and a cleaning unit and a photosensitive drum, and made removably mountable on a main body of an image forming apparatus. Further, the process cartridge is a cartridge obtained by integrating at least a developing unit and a photosensitive drum, and made removably mountable on a main body of an image forming apparatus.
The developing device is a device obtained by integrating a developing unit for developing an electrostatic latent image formed on a surface of a photosensitive drum, a developing frame body for supporting the developing unit, and a component associated with the developing unit, and made removably mountable on a main body of an image forming apparatus.
The developer container is a unit for containing developer used for an electrophotographic image forming process. The developer container contains the developer. The developer container includes a stirring conveyance unit for delivering the developer contained in the developer container.
Description of the Related Art
In an image forming apparatus using an electrophotographic image forming process, a cartridge type for making a cartridge such as a developing cartridge or a process cartridge removably mountable on a main body of the image forming apparatus has been used.
An example of a developing device of such a cartridge type is divided into a developing chamber including a developing roller and a supply roller for supplying developer to the developing roller and a containing chamber that contains the developer, and has an opening for communicating the developing chamber and the containing chamber with each other.
A sealing member seals the opening to close the containing chamber in the developing device until a user starts to use the cartridge. When the user uses the cartridge, the developer can be conveyed into the developing chamber from the containing chamber by peeling the sealing member from the opening. As a method for peeling the sealing member from the opening, various configurations have been proposed.
For example, Japanese Patent Application Laid-Open No. 5-197288 discusses sealing an opening for communicating a developing chamber and a containing chamber with each other using a sealing member and unsealing the sealing member using a rotary member provided in the containing chamber. The sealing member is unsealed by making its one end adhere to the rotary member. When the rotary member rotates, the sealing member is rewound and peeled from a peripheral edge of the opening. The sealing member rotates integrally with the rotary member after being unsealed.
However, in a comparative example illustrated in FIG. 8, to explain a method for peelably fixing one end portion 180e of a sealing member 180 to a peripheral edge of an opening 31h in a partition wall 31i, a fixing portion to an upper edge of the opening 31h in the partition wall 31i illustrated in FIG. 8 is a first fixing portion 31j. A fixing portion to a lower edge of the opening 31h in the partition wall 31i illustrated in FIG. 8 is a second fixing portion 31k. 
When the sealing member 180 is peeled by the rotation in a direction indicated by an arrow H illustrated in FIG. 8 of a conveyance member 136, an unsealing fulcrum 136g of an unsealing member 136e is as follows. The unsealing fulcrum 136g of the unsealing member 136e when the sealing member 180 is peeled and a rotation center 136h of the unsealing member 136e are set on the same side with respect to a virtual plane E including the first fixing portion 31j and the second fixing portion 31k. 
Thus, the sealing member 180 cannot be peeled along the virtual plane E parallel to a surface of the opening 31h formed in the partition wall 31i in a developing frame body 31, and needs to be peeled at a predetermined angle θ (>0) to the virtual plane E.
When the sealing member 180 is peeled at the predetermined angle θ (>0) to the virtual plane E parallel to the surface of the opening 31h, a large peeling force is required. Further, the sealing member 180 cannot be stably peeled from the peripheral edge of the opening 31h. Therefore, a surplus portion (e.g., remaining thread) of the sealing member 180 may occur.
As in the comparative example illustrated in FIG. 8, if a peeling force of the sealing member 180 is large when the sealing member 180 is peeled from the peripheral edge of the opening 31h in the partition wall 31i, a rotation load of the unsealing member 136e in the conveyance member 136 in the containing chamber 31f becomes large.
When the rotation load of the unsealing member 136e increases, a load on a motor provided in the main body of the image forming apparatus 100 that drives the conveyance member 136 to rotate increases. Accordingly, an output of the motor in the main body of the image forming apparatus 100 needs to be increased. Therefore, the size and the cost of the motor may be increased.